"The most commonly cited signs [of pure-blood status] were...dislike or fear of pigs and those who tend them (the pig is often considered a particularly non-magical animal and is notoriously difficult to charm)..."

A pig, or swine, is a type of animal in the biological family Suidae. The pig is considered to be a difficult animal to charm and thus incredibly non-magical. It is for this reason that certain 18th century works considered dislike or fear of pigs to be a sign of pure-blood status.[1]